Battery Size (replacing)

I use 2 GC2 (golf cart) batteries. They are 6 volt and a true deep cycle battery. They are also more durable if they get ran down. I run a resi fridge and do not boondock.
The truck does charge the battery on the road, but I don’t think it supplies as much power as the fridge uses. The 2 gc2 batteries have held up to a 16 hr drive.

Group24 is about 75 AH give or take a few
Group 27 is the low side of 100
Group 29 is the high side of 100
Group 31 is about 130

You may safely use about 1/4 of a MARINE/deep cycle type battery

GC-2.. I a six volt golf car battery that is about the same size as a Group 24 but a bit taller.. If you have the room then-{6v}+-{6V}+==12 volts at 220 amp hours (Give or take) and you can safely use about half.

LiFePO4.. Not sure how many amp hours they can put in a 24 size (Guessing abourt 100) and of those 100 you can use 90-95 Man need a different converter however.

Campinfan wrote:
I do not boondock but the battery is used to run my inverter to power my residential fridge when driving. I know the truck supplies the power when driving. I guess if it will fit in the box, I will go a little bigger. and thanks for the MCA definition.

Is this the starting battery for a motorhome/truck or is it the house battery for a trailer (or non-engine loads in a motorhome)?

I'm guessing since you mention the fridge, it's the house battery.

A few clarifications:
- CCA and MCA are all about starting the engine. Overly simplified, if you ask the battery to put out as many amps as possible, this is how much it will put out. A big diesel often comes with 2 batteries as it takes a lot more amps to spin the engine fast enough to generate compression ignition vs a gas engine that relies on a spark to ignite the fuel/air mixture. This can easily be in the hundreds of amps.
- Amp-Hour rating is how long the battery can output power (at an assumed amperage, though much lower than the amperage for starting a truck engine). This would be a good estimate for how long it could run something like a fridge that might be drawing 10amps but for a long time.
- Then you have starting, marine and deep cycle batteries. This is the internal structure of the battery. Starting batteries use many thin lead plates as more surface area generates more amps. Deep cycle batteries use fewer thicker plates as thicker plates can hold more stored energy. Marine (aka: Combo) are generally starting batteries that have been relabeled starting batteries that have a wing nut attachment on the studs. It's almost impossible to find true deep cycle 12v batteries. Usually, people will get 6v golf cart batteries and wire them in series to generate 12 if they really want deep cycle.

For your use, the $4 upgrade is probably fine but don't expect much difference in amp-hr. Reality is your truck will keep the battery topped up and the battery will power the inverter, so it doesn't make much difference. For that use, I typically buy the cheapest battery available as there is negligible difference.

If you start boondocking more (aka: no shore power), that's when bigger and better battery banks become useful.

RLS7201 wrote:
Marine/RV batteries are compromise batteries. They were developed for marine trolling and engine start. They do not excel at either.
For you application a standard lead cell starting battery is your bet choice.

Richard

You’re right about the first part, sort of. They’re actually just fine for starting and will take the short term high amp loads just fine but they’re a compromise for deep cycle/ house battery use like trolling motors and campers because they have more/thinner plates to accommodate the high amp loads.
Second part you’re completely off/backwards. A dedicated starting battery while it will do the same job as a deep cycle, it won’t do it near as long before it’s worn out. That’s why true deep cycles aren’t suitable for high amp starting loads. They have thicker plates that last longer under discharge conditions that a good operating starting / charging system keeps from happening.

Find it hard to believe that big ole camper only came with one battery. That’s largely useless if the camper is being used for more than a couple hours tops off of shore power.

Marine/RV batteries are compromise batteries. They were developed for marine trolling and engine start. They do not excel at either.
For you application a standard lead cell starting battery is your bet choice.

Richard

Campinfan wrote:
I do not boondock but the battery is used to run my inverter to power my residential fridge when driving. I know the truck supplies the power when driving. I guess if it will fit in the box, I will go a little bigger. and thanks for the MCA definition.

Your truck doesn’t directly supply the “power” when driving, and unless you’ve done considerable charging modifications, it supplies only a very low amp charge to your trailer battery if everything works Ike it should.
Not even close to what the inverter pulls off the battery to keep the fridge going in the dead of summer. Maybe winter too.
Now if you only drive a couple/few hours between being plugged into shore power and plugging into shore power again, yes you can continue getting by with a little single battery.

But do/will you ever drive all day long, maybe have a 24hour lapse in shore power? If so your setup even with a bigger battery won’t cut it.
I only mention this because the battery(s) are the biggest part of the equation you mention and if it’s time to get a new battery, it’s the best time to think about whether what you have will continue to work well for what you need.

After having many different brands of this size battery, this is the one I'd recommend. Good power, and very long lasting.

Jerry

I do not boondock but the battery is used to run my inverter to power my residential fridge when driving. I know the truck supplies the power when driving. I guess if it will fit in the box, I will go a little bigger. and thanks for the MCA definition.

You can replace with any 12volt battery you want. You should first determine the physical size of the battery and if it fits within the space it will reside in.
MCA = marine cranking amps Clicky